The paper presents a new method for generating typologies of formal-ontological relations. The
guiding idea is that formal relations are those sorts of relations which hold between entities
which are constituents of distinct ontologies. We provide examples of ontologies (in the spirit
of Zemach’s classic “Four Ontologies” of 1970), and show how these can be used to give a rich
typology of formal relations in a way which also throws light on the opposition between threeand four-dimensionalism.